Bioefficacy of Neonicotinoid Insecticides against Thrips, Scirtothrips dorsalis and Leafhoppers, Empoasca kerri in Groundnut

Bioefficacy of systemic insecticides of neonicotinoid group viz., imidacloprid, acetamiprid, and thiamethoxam as foliar sprays was evaluated on groundnut sucking pests with reference to thrips (Scirtothrips dorsalis Hood), and leaf hoppers (Empoasca kerri Pruthi) against conventional pesticide, monocrotophos and unsprayed control at 25 and 40 days of the crop stage. This study indicated that application of imidacloprid @ 26.7 g a.i ha−1 at 25 and 40 days after sowing was found to be significantly effective in reducing thrips and jassid populations. Imidacloprid was found significantly superior among various neonicotinoid compounds due to its quick action and persistence until 8 days after application. Maximum reduction of (80%) population in thrips at one day after application and 90% at 8days after application was noticed which was significantly superior over the other neonicotinoid compounds. Application of imidacloprid @ 26.7 g a.i ha−1 showed 90% and 93% reduction at one day and 8 days after application against jassid population. Similar trend in the efficacy of imidacloprid was also noticed in the second round of application at 40 days of the crop against both the species. After 15 days of application all the chemicals tested revealed similar effect in reducing the thrips populations, however there were significant effects of these chemicals on jassid populations. In general, neonicotinoids, showed higher efficacy in reducing thrips and jassid populations with increased pod yield in groundnut compared to conventional monocrotophos.